Problem: Luis ate 3 slices of pie. Ishaan ate 2 slices. If there were 4 slices remaining, what fraction of the pie was eaten?
Answer: $\text{fraction of pie eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ Since they ate 5 slices of pie with 4 slices remaining, they must have begun with 9 slices. They ate ${5}$ out of $9$ slices. They ate $\dfrac{5}{9}$ of the pie.